DFS2356W IOSB OR ITASK BLOCKS COULD NOT BE ACQUIRED

Explanation
 Sequential Buffering (SB) was unable to acquire
enough OSAM IOSB or ITASK-related control blocks to provide the maximum
amount of overlapped I/O.

System action
 The amount of overlapped SB I/O for the application
program or utility is limited.

User response
 If message DFS2342I was previously issued, investigate
using a larger value for the IOB parameter when you start the IMS batch
JCL procedure.